Feminine hygiene absorbent personal care articles are often used to collect and retain body fluids, liquids or exudates containing menses or blood. In the context of such products, comfort, absorbency, and discretion are three main product attributes and areas of concern for the wearer. In particular, wearers are often interested in knowing that such products will absorb significant volumes of menses exudates in order to protect their undergarments, outergarments, or bedsheets from staining, and that such products will help them avoid the subsequent embarrassment brought on by such staining. Wearers are also interested in using products that cannot be seen or felt through their undergarments.
Feminine hygiene absorbent personal care articles, such as sanitary napkins, pads and pantiliners, typically include at least one or more absorbent layers enclosed between a body-facing, liquid permeable topsheet layer and a garment-facing liquid impermeable backsheet layer. The edges of the topsheet and backsheet layers are often bonded together at their periphery to form a seal around the article to thereby contain the absorbent layers and any exudates received into the article through the topsheet. In use, such articles are typically positioned in the crotch portion of an undergarment for absorption of bodily exudates, and are held in place via adhesive strips positioned on the undersurface of the articles (facing the garment). Some of these articles also include wing-like structures for wrapping about the user's undergarments to further secure them to a user's underwear. Such wing-like structures (also known as flaps or tabs) are frequently made from lateral extensions of the topsheet and backsheet layers.
For many women, it is entirely routine to periodically view their feminine hygienic articles during use, so as to monitor the appearance and spread of a menses insult (so as to avoid leakage throughout the day). For some women, a concern or cause of emotional discomfort with conventional feminine hygiene absorbent personal care articles is the expanding appearance of a menses insult in the article, and specifically, the spread of the menses stain to the side edges of a product. While many women often do not mind seeing a targeted stain in the center of a pad, and then change the pad accordingly, some women prefer not to see an extensive stain, other than the centralized insult stain. In contrast, some women prefer to see an expanding stain, as this provides indication of their level of flow that day, as well as evidence that the pad is collecting such exudates. Obviously, the leakage of fluids when using such articles, particularly from around the side edges of the articles, is universally a cause of emotional concern. Such leakage may occur in the narrower product dimension along the longitudinally directed side edges, or along the wing or flap areas. Product leakage may lead not only to embarrassment for the consumer, but also to a general loss of confidence in use of the articles.
Various attempts have therefore been made to incorporate chemistry or structures into feminine hygienic pads to separate staining, direct staining, target staining, mask staining or discolor menses staining; to make more efficient use of as much of an absorbent product as possible; and to reduce or prevent leakage. Such structures include embossed walls or channels, printed target areas, polymeric or other liquid impermeable barrier walls, and the like. However, such attempts have not been completely successful at eliminating or addressing the leakage problem, or reducing consumer concerns over staining, if it actually were to occur.
Attempts have also been made to chemically alter and separate components of menses along the depth direction of a pad, and thus reduce the mental impact of a possible stain, should menses strike through an absorbent layer to the bottom of a sanitary napkin. For example, U.S. Pat. No. 3,124,135 to Olson, discloses the use of salts on a pad's interior layers (salt layer sandwiched between absorbent core layers and having the same lateral dimensions of the absorbent layers), so as to decolorize menses by precipitating the darker colored hemoglobin of the menses, as fluid travels in the depth direction of the pad. Such decolorization allows almost clear menses liquid to flow to various portions of lower absorbent layers and away from the precipitated hemoglobin. Such decolorization also allows clear menses liquid to potentially flow through a lower absorbent layer to the bottom of a pad, thereby reducing the occurrence of a visible stain at the bottom of a pad. The Olson reference highlights the stiffness produced in a pad as a result of the interior salt-containing layers, and offers a pad softening-solution, by use of polyethylene glycol (hereinafter PEG) as an additional element with the impregnated salt elements on the interior layers of a pad. However, even with such salt and PEG combinations, the placement of this agglomeration chemistry on, or immediately near the absorbent layers, and having the same lateral dimensions as the absorbent layers (along the depth axis), can lead to the blocking of absorbency pathways in an article. Possible leakage may then result from the redirected fluid. The Olson reference does not address staining that results from pad leakage off of the pad top surface, either as a result of fluid flow or saturation of a subjacent absorbent layer. Nor does the Olson reference address the concern of consumers that would rather limit their viewing of a stain in a pad, when viewing a pad from the topsheet layer surface. United States patent publication 2012/0165773 to Nakashita et al. also describes placement of chemistry within the core layer. A further reference which describes an alternative technique for filtering using a “depth filter” is U.S. Pat. No. 6,350,711 to Potts et al. Still another reference which describes the use of specific salts to remove colored substances from aqueous fluids is U.S. patent publication 2012/0215192 to Corbellini et al. Despite these references, there is still a need to lessen leakage, and to alter the stain-producing fluid off of a feminine hygienic pad top surface, so as to lessen the mental impact of a menses insult (and potential leakage stain) for pad users, without interfering with the functioning of a product's absorbent layers; there is also a need for such alteration of the stain-producing fluid without impacting product “feel” that may be impacted by the addition of salts; and there is also a need for a pad which limits staining potential as well a consumer's view of a stain within the pad.
Numerous absorbent structures have also been developed for capturing and retaining voluminous menses exudates released by women during their monthly cycles. In this regard, the designs of such absorbent pads and pantiliners have been refined over time, so as to make their usage more comfortable (physically and emotionally) to consumers. For example, originally when first developed, catamenial pads were thick and bulky structures, typically using cellulosic wadding as their sole or primary absorbent layer, such as described in U.S. Pat. No. 3,124,135 to Olson. Such pads were often readily visible through a wearer's outergarments, were used in conjunction with separate belts or tabs, and proved uncomfortable for a user to wear. These older “tabbed” or belted pads distributed menses predominately in the depth direction of the pad, and predominately leaked through the back (bottom) layer of the pad. This fluid distribution was driven by a close to the body fit, due to the pad use with belt construction. These pads were typically over ¾ inch thick, and employed no impervious layers to impede menses or air movement through the pad, and offered no specific distribution materials to drive lateral or longitudinal fluid distribution. The older pads needed constructions that prevented downward distribution of the red stain of menses. These pads also did not contain any superabsorbent that might interfere with the distribution of menses within the pad. As a result, such older constructions would not work adequately on modern, garment-attached pad arrangements.
As absorbent technology advanced, superabsorbent polymer chemistry and substrate layering designs have been developed, enabling manufacturers to produce feminine absorbent products with progressively thinner configurations. As a result, feminine hygiene sanitary napkins, pads and liners have become significantly thinner and more absorbent, so as to impart both comfort and a certain inconspicuousness to a wearer. For the most part, such thinner products have provided the users and surrounding third parties, with the impression that the user is not wearing any form of menses protection in her undergarments. Such articles have employed various garment attachment systems.
The modern garment-attached pads predominantly distribute menses laterally and longitudinally, and, when they leak, predominantly leak off the side edges (longitudinally directed sides, front, and back) rather than through the pad bottom. This leakage distribution is driven in part by not-so-close pad body fit, due to attachment to underwear or panties, and the pad construction. These pads are typically less than ¼ inch thick, have an impervious layer to impede menses and air movement through the pad, and utilize specific distribution materials to drive lateral and longitudinal distribution. Modern pads also contain superabsorbent that can interfere with the distribution of menses within the pad. The use of superabsorbent materials in core layers can lead to gel blocking that interferes with maximized fluid absorption.
Even with these advancements in absorbency, consumers continue to experience some leakage, typically from fluid run-off from the topsheet surface. Such run-off is often the result of various “structural” and “action-based” root causes, which cause soiling of user garments or bedding. For example, structural causes may include impeded absorbency pathways, or inability to handle fluid surges. Action-based causes may be for example, consumers experiencing leakage from improper placement of such products in their undergarments, a consumer's use of such products beyond the product's designed lifespan, consumers choosing to wear an absorbent article that is ill equipped to handle their current menses flow rate, or further still, consumer movements during their daily activities which cause menses exudates to leak off of the absorbent article. Therefore, despite the development of many different absorbent technologies and structural designs, product leakage and the resulting stains caused from such leakage continue to concern potential users of such products. Mere adaptation of older decolorization technology to modern pad structures would not be adequate, as it does not account for interference from modern superabsorbents (superabsorbent competes with the decolorization technology for the menses), lack of adequate surface area, and modern day pad menses distribution, to prevent locally overwhelming the decolorization technology. A need therefore exists for pad constructions that prevent lateral and longitudinal distribution of the red stain of menses.
Certain sensors or condition change indicators are known for use with feminine hygiene absorbent articles and other types of absorbent articles, to notify a user or caregiver of the impending need to change such article as a result of a change in condition. Such devices may assist in providing consumers with calmed emotional states, knowing that the devices are actively communicating impending product failure or body states. Such indicators can be seen for example in U.S. patent publications 2003/0130631 to Springer and 2007/0055210 to Kao. While, such devices are focused primarily on preventing leakage or staining, or the onset of some other condition by limiting user wear time, such devices do not assist in altering potential staining, should leakage actually occur. There is therefore a further need for such products which would reduce consumer emotional concerns of such staining, and the embarrassment that might accompany such staining if it were to occur.
As previously described, certain chemistry for the decolorization of blood stains on absorbent articles is known. For example, colorant changers, neutralizers or decolorizing compositions are described in U.S. patent publications 2008/0277621 to MacDonald, 2009/0061718 to Seidling, 2009/0062764 to MacDonald, WO2009133518 to Cunningham, U.S. Pat. No. 6,730,819 to Pesce, U.S. Pat. No. 7,105,715 to Carlucci, U.S. Pat. No. 3,124,135 to Olson, U.S. patent publication 2011/0004174 to Carlucci, and WO2011027295 to Corbellini, each of which are hereby incorporated by reference in their entirety. Such chemistries are often difficult to place uniformly on a product surface, or to manipulate into a high enough surface area. Further, such chemistries may often result in a heavier, stiffer, and a subsequently more uncomfortable feeling article. Finally, such chemistries may result in menses color alterations that are less desirable to a consumer. Therefore, even with these available chemistries for decolorization, there is a further need for absorbent structures which utilize both layering structures and chemistry, to reduce the severity/appearance of menses staining of both a user's pad, and a user's garments or bedding. There is also a need for absorbent articles which reduce a consumer's concern over any stain that might occur, as well as articles which more efficiently use absorbent systems to take up retained liquids.